125 



to be of small accoiuit, the direction of the coastline being mainly 

 E.-W. ; on the otiier hand the Espj'-Köppen eflfect ought to be fairly 

 well the same for both components. However, the sea wind blowing 

 N.-S. exercises its intluence on the East West component, in such 

 a manner that the air above the sea, which is little or not 

 susceptible to the Espy-Köppen etfect, is forced landward, thereby 

 diminishing its effect above the land in tiiose layers where sea 

 breezes occur. 



The following phases of the diurnal oscillation of the East com- 

 ponent clearly show the intluence of the Espy-Köppen effect. 



Though in a smaller degree, the curves of the semidiurnal 

 variation also distinctly show the influence of both phenomena of 

 land and sea breezes and of the Espy-Köppen effect. 



The main reason for this is probably that both phenomena do 

 not run purely sinus-like, but deviate from it sufficiently to 

 produce an important semi-diurnal term when applying harmonic 

 analysis. Indeed both phenomena chiefly originate in insolation to 

 and radiation from the earth, which do not run purely semidiurnal. 



The graphs distinctly show that these influences make them- 

 selves felt principally below 3 km. and may be neglected above 

 4 km. Therefore, if we wish to arrive at results for the lower, 

 layers, not disguised by either of these effects, it will be necessary to 

 operate far from the land and above the open sea, because here 

 the}' are both absent. 



Eventually we proceeded to these observations and the last mentioned 

 of us together with the observator J. H. Kats started a series of ascen- 



